FDA Approves Pexidartinib as First TGCT Therapy

The US Food and Drug Administration (FDA) has approved pexidartinib (Turalio) capsules for the treatment of symptomatic tenosynovial giant cell tumor (TGCT) in adult patients.

The indication, which specifies to patients who are unresponsive to surgery and who suffer from TGCT associated with severe morbidity or functional limitations, marks the first for the rare joint tumor condition.

TCGT affects the synovium and tendon sheaths, and though it is rarely malignant, it causes the 2 layers to thicken and overgrow, damaging surrounding tissue.

The FDA approved pexidartinib based on the findings of an international, multicenter study involving 120 patients split to either therapy or placebo. Investigators assessed for a primary efficacy endpoint of overall response rate (ORR) post-25 weeks of care.

Of the patients treated with pexidartinib, 38% reported statistically significant improvement in ORR, versus none in the placebo group. Another 15% of treated patients reported complete response, and 23% reported partial response.

Of the 23 patients followed for at least 6 months, 22 maintained response, and all 12 patients followed for at least 12 months maintained their response.

Turalio’s prescribing information includes a Boxed Warning label, advising prescribers and patients to consider the serious and potentially fatal liver injury risks associated with the drug. The FDA advises physicians monitor liver tests prior to initiating therapy, as well as at specified intervals of treatment.

The therapy will only be made available through the Turalio Risk Evaluation and Mitigation Strategy (REMS) Program.

Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence, and acting director of the Office of Hematology and Oncology Products for the FDA’s Center for Drug Evaluation and Research, commended the first therapeutic approval for TGCT, which can compensate for the population of patients who do not benefit from the primary care option of surgery.

"TGCT can cause debilitating symptoms for patients such as pain, stiffness and limitation of movement,” Pazdur explained in a statement. “The tumor can significantly affect a patient's quality of life and cause severe disability.”